Compost got too many worms?

I'm reasonably good at building compost heaps - they don't smell, the end product is dynamite for the garden, and they are chock full of worms. But, my compost heap is not heating up any more, not even when I add new material. I compost EVERYTHING except humanure (I'd do that too, but there is no space in my bathroom to keep the buckets). I probably add four to six gallons of material every week, mostly kitchen scraps, and in the year or so since I built the heap, the new material has always heated up within a few days, usually to about 45degrees celsius. For the last month or two, the new material has only heated about five degrees above the background temp of the heap. Here are my theories, would appreciate your feedback:

#1 - too many worms. The heap is incredibly full of compost worms - could they be eating the newly added materials before they have time to heat up? A lot of the stuff I add has started to decompose so I imagine it looks like heaven to the wriggly beasts.

2# - it's winter. It is a big heap, more than a cubic meter, so should have enough mass to self-insulate, but maybe not. However, it was winter when I originally built the heap, and it got as hot as 66 degrees Celsius, so would surprise me if the outside temp is the problem.

3# - lower layers are quite compacted. The bottom thirty centimetres or so is quite compacted and much damper than the rest of the heap - could that be sucking heat away from the top parts of the heap?

Worms eat anything they can put in their mouths for the most part. Bacteria, fungi, organic matter get eaten. If you have too many worms, they will probably distrupt the bacteria being able to multiply.

Welcome to permies Lizzie
Has your compost stayed hot through the winter in the past?
Speaking of winter, the compost isn't too sodden is it?
It seems to me that worms would be the result of #2, 3 and possibly other conditions, since they don't like it too hot.
I can't imagine them being the cause of a compost heap not heating.
I generally build heaps over time so they don't get properly 'hot' and there's always a lot of worms.
I usually only turn it once or twice: when the bin gets overly full, I collect a load of high nitrogen material
and turn the pile into an empty bin, adding nitrogenous material as I go.
I always find some pretty whiffy anaerobic spots toward the bottom...
It always heats up quite a bit after that, and the worms probably move out for a while!

#1 - too many worms. The heap is incredibly full of compost worms - could they be eating the newly added materials before they have time to heat up? A lot of the stuff I add has started to decompose so I imagine it looks like heaven to the wriggly beasts.

There are 2 ways to compost. You can build a pile and let it heat up, or you can vermicompost. If you have enough worms, they will take care of all of the organic material without the pile needing to heat up. A compost pile or bin that's primarily run by worms can and does heat up sometimes, but generally vermicomposters are happy that the bins don't heat up too much so that your worms don't get killed off. If you really do have too many worms, you can divide them into two containers or piles and build your throughput.


2# - it's winter. It is a big heap, more than a cubic meter, so should have enough mass to self-insulate, but maybe not. However, it was winter when I originally built the heap, and it got as hot as 66 degrees Celsius, so would surprise me if the outside temp is the problem.

If it's winter where you are, and the worms are doing just fine, then you don't have to worry about insulation.

3# - lower layers are quite compacted. The bottom thirty centimetres or so is quite compacted and much damper than the rest of the heap - could that be sucking heat away from the top parts of the heap?

Worms work from the bottom up. If you start out with, say 5 cm of bedding/organic material, the worms will process that, and then as you add more material, they will move up to the new material. After a while, it piles up, and the worms are still working in the upper parts. The lower parts will have been processed by the worms and the worms won't be much interested in it, except if they need to escape from something, like hot pocket in the bin/pile.

The lower layers become compacted because they've got the upper, active layers sitting on top, and there's little worm activity. The lower layers become more damp because water flows downward. The upper layers can still become plenty hot if the conditions are right, despite extra moisture below.

Personally I see nothing wrong with letting your worms do the work. The castings they leave behind are an excellent nutrient source for the garden. And as long as you're not smelling a foul odor, then the pile is doing fine. It does not have to heat up in order to decompose. The only reason I run some hot compost piles is to process material that may be full of unwanted seeds or contain manures that might contain parasite eggs. Since I don't use commercial farm manures, I don't need to worry about killing dangerous pathogens that proliferate many commercial operations. More than half of my composting effort goes into cold or cool composting.

Since most people complain about not having enough worms, I guess you earn a gold star! You must be doing something right. Congrads!